Carbamic acid,[2-[[1-[[(2,3-dihydrospiro[1H-indene-1,4'-piperidin]-1'-yl)sulfonyl]methyl]-7,7-dimethylbicyclo[2.2.1]hept-2-yl]amino]-2-oxo-1-(3-thienylmethyl)ethyl]-, 1,1-dimethylethyl ester